Method for treatment of tobacco smoke



United States Patent 3,409,018 METHOD FOR TREATMENT OF TOBACCO SMOKE Marvin M. Smith, 1010 E. Parkway Drive,

' Muncie, Ind. 47302 No Drawing. Continuation-impart of abandoned application Ser. No. 585,712, Oct. 4, 1966, which is a continuation of application Ser. No. 351,531, Mar. 12, 1964. This application Mar. 14, 1968, Ser. No. 712,971

5 Claims. (Cl. 131-9) ABSTRACT OF THE DISCLOSURE A method for treating the smoke of a burning cigarette to cause the condensate particles of the volatile constituents thereof to increase in size within the body of the cigarette so that a major portion of such particles will be of a size greater than one micron in diameter and be trapped more readily on the mucous membranes of the smokers mouth whereby the amount of the condensates likely to enter the smokers lungs is minimized.

Cross reference to related applications This application is a continuation-in-part of my copending application, Ser. No. 585,712, filed Oct. 4, 1966, now abandoned, as a continuation of my application, Ser. No. 351,531, filed Mar. 12, 1964, and now abandoned.

Background of the invention It is believed by many persons that the inhalation of tobacco smoke, especially the smoke from cigarettes, is one of the causes of lung cancer and emphysema in human beings and for that reason much has been done to provide filters and other mechanical means to entrap, or at least reduce the quantity of, the so-called tars that comprise the sinoke mass. The result, however, has been such a reduction of the taste of smoke that stronger tobaccos have had to be used and this, of itself, has had a tendency to counteract the filtering eltect.

It is known that the aerosol produced by smoking a cigarette at an average rate consists mainly of very fine particles or droplets of the volatile constituents of tobacco, which are the taste producing media, together with water vapor and some solid particles in the form of ash. The median particle size of this aerosol is approximately 0.85 micron and only about thirty percent of the aerosol particles in such smoke are larger than one micron in diameter.

Also, itis known that when a putt of smoke is inhaled into the lungs and held for about five seconds, close to eighty-five percent of the smoke is retained in the smokers respiratory system, the mass-median particle size of the exhaled smoke being about .7 mircon. On the other hand when a normal putt of smoke is simply taken into the buccal cavity and promptly expelled without inhalation, the retention of the smoke particles in the buccal cavity averages about thirty-five percent of the smoke mass, and the mass-median particle size of the expelled smoke is about 1.2 microns. The large particle size of the smoke expelled when the putt is merely .taken into the smokers mouth is believed to be due to coalescence and hygroscopic growth of the droplets while exposed to the saturated atmosphere of the buccal cavity.

This indicates that in the course of ordinary smoking wherein smoke is inhaled for about 5 seconds, which 98 percent of smokers do, the large smoke particles, about 1.2 to 2 microns in size, are normally retained by the buccal cavity and that most of the smoke particles of from 0.7 up to about 1.2 microns diameter pass into and are retained by the smokers lungs.

It appears that the so-called tars contained in tobacco smoke are the evil factors believed to have a carcinogenic effect when introduced into the smokers lungs, and yet it is principally these factors which give the tobacco smoke its taste. Therefore, to maintain the taste, without which smoking would have little or no satisfaction, a 'sufl'icient amount of the tars must be present in the smoke entering the smokers mouth to adequately stimulate his taste buds.

The openings between the conventional cigarette filter fibers have a diameter of about one-hundred microns. The mass-median particle size of ordinary cigarette smoke, however, is less than one micron, and thus, the usual filters only trap some of the tars from tobacco smoke. On the other hand, absolute filters remove all of the tars and remove all of the taste.

On this premise and because the larger smoke particles, more than 1.0 micron in diameter, tend to become deposited on the mucous membranes of the buccal cavity and pharynx, I have found that by causing the normal smoke particles to become increased in size before entering the smokers mouth the amount of smoke passing into and being retained by the lungs can be reduced materially with respect to what it would otherwise be, all without loss of taste.

Since the major portion of the smoke mass normally is made up of particles less than one micron in diameter, the problem is to cause increase in size of these small particles, as by coalescence with each other and with the larger particles, to form enlarged particles of at least 1.0 to 2 microns and more in diameter, and at such a rate that only a relatively small amount of the original smoke mass will remain at the less than one micron size when the smoke leaves the cigarette.

Summary of the invention It is known that in a saturated smoke stream the particles of the condensate will coagulate or coalesce by combining in large numbers of all sizes, that is small particles and large particles joining to form an aerosol comprising principally relatively large globules. This action can be stimulated and accelerated by creating a super saturated gas condition in which condensation of water vapor on the smoke particle nuceli will enhance coalescence of the particles, or growth of particle size. Initially, I attempted to do this by artificially cooling the cigarette smoke to a temperature below the dew point of the water vapor in the smoke stream. I found, however, that this procedure could be improved by adding moisture to the tobacco which, when burned, raised the dew point of the resulting smoke to where merely normal cooling of the smoke to about ambient temperature would cause condensation of the water vapor onto the particles in the smoke stream. Unfortunately, however, an excess 3 of moisture in the tobacco, caused bacterial and fungus growth and a spoiling of the tobacco. Therefore, a means had to be found to add water in a way that it would be in the cigarette, not in contact with the tobacco, but so that it could be released in a controlled manner at the time it is needed.

The result is that I have found that this can be done by adding discrete amounts of water to th cigarette tobacco in the form of microencapsulated water particles distributed along the length of the cigarette, which water particles become released progressively, as immediate vapor, upon buming of the tobacco and at a rate directly related with the consumption of the tobacco. Such added vapor will raise the dew-point of the smoke stream 50 that a supersaturated condition of the gas will occur continuously within the cigarette, originating immediately adjacent the combustion zone, and result in rapid condensation of moisture and accelerated coalescence of the smoke particles. Thus a greater part of the smoke issuing from the cigarette into the smokers mouth would have a mean particle size greater than 1.0 micron and be more readily caught in the buccal cavity.

It will thus be seen that the purpose of my invention is to minimize the amount of the harmful components of cigarette tobacco smoke, likely to enter the smokers lungs, by artificially increasing the particle size of such components, whereby they are more likely to be caught by the mucous surfaces of the smokers mouth and upper respiratory tract, and to accomplish that purpose at the earliest possible moment by causing a saturated condition of the smoke stream as it is created.

Description of the preferred embodiments A preferred method for supplying the water to the cigarette body for accomplishing my improved smoke treatment process is to use micro-encapsulated globules of water, of an appropriate size and amount, uniformly distributed throughout the shredded tobacco mass from which the cigarette is made, the encapsulating material being capable of decomposition by pyrolysis in the cigarette. Another method is to apply the capsules as a uniform coating on the inside of the cigarette paper or wrapper.

The size of the water globule capsule may be up to 1500 microns in diameter, to stay within a water volume range per globule that can be instantly vaporized by the burning tobacco ember upon rupture of the capsule, without danger of extinguishing combustion, even while the cigarette is not being puffed. The number of capsules to be supplied for each unit of cigarette length will depend, of course, upon the capsule size and the amount of water to be supplied for optimum smoke treatment results. The smaller the capsules, the better can be their distribution.

I have found that with a normal cigarette having 1.02 grams of tobacco the added water may be as much as will provide a ratio of about 28% water and 72%, by weight, of shredded tobacco, as ordinarily prepared for cigarettes, to produce an increase, above normal, of the mean particle size of the condensable components of the tobacco smoke. The optimum amount of added water appears to be about to by weight, of the said shredded tobacco because of varying tobacco conditions likely to be met. To maintain normal combustion in the burning cigarette, it has been found that the amount of water added should not be more than about 28%, by weight, of the shredded tobacco.

The encapsulating material or the coating of the water globules should be substantially tasteless in the tobacco smoke and wholly non-toxic when burned. This material must also be of sufficient strength, for a capsule of minimum wall thickness, to withstand normal processing of the tobacco during manufacture of the cigarette, and sufficiently elastic to withstand freezing without bursting.

or in contact with the tobacco,

4 Suitable materials for this purpose,-and from which the encapsulated water globules may be readily made by conventional methods, will include edible glyceride, polyethylene, ethyl cellulose, guar gum and various waxes.

Regardless of the particular way employed to enhance particle growth in the smoke stream, the purpose is to obtain a maximum reduction of the percentage of small particles in the aerosol mass, less than one micron in size, which small particles normally constitute about or more of the untreated smoke mass. These are the particles, mainly of about 0.7 to about 1.0 micron in size, which enter into the smokers respiratory system upon normal inhalation and of which a major portion are retained in the smokers lungs after exhalation following a 5-second pause. Ordinary filters will remove most of the large size particles of 2 or 3 microns size but the' bulk of the tars are contained in the 70% of the smoke mass which is under 1 micron in particle size. l

By artificially increasing the particle size of the smoke stream so that a major portion of the particles are greater than 1 micron in diameter, and wherein the mass-median particle size is about 1.25 microns, it appears from numerous tests that the buccal retention of the particles which are more than 1 micron in size is raised to at least 62%. Thus taste is maintained while the deleterious material going to the lungs is minimized.

From the foregoing it will be apparent that in the usual smoking of tobacco, as in ordinary cigarettes,v it is the medium size and larger smoke particles, or globules of tar, 0.7 to 1.0 micron in size when entering the mouth, that are likely to go into and be retained in the smokers lungs. The very small globules or particles approximating 0.5 micron in size are generally expelled in normal smoking and are thus substantially harmless, while the large particles, 1.0 micron and more in diameter, are generally trapped in the smokers mouth from which they pass into the alimentary system. At present, there is no indication that this is harmful to the tobacco user. Because of diffusional forces, the smoke particles less than 0.4 micron in size go into and are usually retained in the smokers lungs. However, they comprise such a small part of the smoke mass as to be of insignificant effect.

The main advantages of my invention reside in the fact that the allegedly harmful effects of cigarette smoking are minimized by trapping the major part of the smoke tar constituent in the smokers mouth rather than letting it enter the lungs, thereby retaining the full effect of taste and allowing only a sufficient amount of the smoke to reach the smokers lungs as to afford a smoking sensation.

In the conduct of the tests of my herein disclosed invention, test cigarettes were smoked at a smoke draw rate of 17 /2 cc. per second with the average puff being 35 cc. The cigarettes employed were stored at room temperature prior to test and each cigarette contained 1.02 grams of tobacco.

Normally the smoke from a cigarette, being smoked at an ordinary rate, will leave the cigarette at almost ambient temperature, i.e. 70 to F. The temperature at the fire zone is approximately 850 C. but the smoke cools to about ambient temperature during its travel in the cigarette.

I claim:

1. The method of treating tobacco smoke in a burning cigarette to facilitate entrapment of particles of the volatile matter thereof in the smokers mouth which comprises the step of adding water vapor to the smoke stream continuously and simultaneously with the burning of the tobacco by pyrolysis of micro-encapsulated globules of water to substantially saturate the smoke stream as it is created and thereby stimulate the growth of size of said particles by accelerated coalescence of the particles before they enter the smokers mouth.

2. The method according to claim 1 wherein the water vapor is condensed onto the said smoke particles to aid their growth of size.

3. The method according to claim 1 wherein the water vapor in the smoke stream is condensed onto the said smoke particles and the majority thereof become larger than one micron in diameter.

4. In the method of claim 1, wherein the burnable mixture comprises essentially about 75 to 80 percent by weight of shredded tobacco and about 20 to 25 percent 10 by Weight of micro-encapsulated globules of water.

5. In the method of claim 4 wherein the encapsulated water globules are of size less than 1500 microns in diameter.

6 References Cited UNITED STATES PATENTS FOREIGN PATENTS 3/1964 Sweden.

MELVIN D. REIN, Primary Examiner. 

